[virglrenderer-devel] coherent memory access for virgl

[Tomeu Vizoso]

On 3/8/19 2:08 PM, Gerd Hoffmann wrote:
> On Fri, Mar 08, 2019 at 10:43:04AM +0100, Tomeu Vizoso wrote:
>> On 10/11/18 1:04 PM, Gerd Hoffmann wrote:
>>>
>>>> * virtio-gpu resource IDs are placed by the guest proxy in the wl_dmabuf
>>>> protocol stream instead of (guest) dmabuf FDs. The proxy in the host
>>>> replaces those to the corresponding (host) dmabuf FD.
>>>
>>> Yes.
>>
>> Hi Gerd,
>>
>> how were you thinking that we would prevent a malicious guest from
>> connecting to the host proxy via VSOCK and guessing virtio-gpu resource IDs?
> 
> Each virtio-gpu device (and therefore each guest) has its own resource
> id namespace, so you can't guess IDs of other guests.  Guessing IDs of
> other processes in the same guest is probably possible.  I think that
> doesn't allow actually accessing these resources, you can only ask the
> host to do something with them.
> 
> Maybe that is a good reason do make wayland proxying a virtio-gpu
> extension.  That way guest userspace would not deal with virtio-gpu
> resource IDs but with gbm handles, and the virtio-gpu drm driver would
> translate gbm handles to resource ids before proxying buffer control
> messages to the host side.

By virtio-gpu extension you mean adding ioctls to send and receive 
protocol data along with references to buffers?

Thanks,

Tomeu